1. Farrer Centre for Conservation Farming, Charles Sturt University, and CRC for Weed Management Systems, Wagga Wagga, NSW 2678, Australia,
2. NSW Agriculture, Agricultural Institute and CRC for Weed Management Systems, Wagga Wagga, NSW 2650, Australia,
3. School of Science and Technology, Charles Sturt University, Wagga Wagga, NSW 2678, Australia